Bucket dredge



July 21, 1942. cc. CLINE ET AL BUCKET DREDGE Filed April 5, 1940 3 Sheets-Sheet l Fi igij INVENTORS Charles C. C I z'ne Leon P. Pz'card .MI; W22

ATTORNEYS July 21, 1942; c. c. CLINE ET AL BUCKET DREDGE Filed April 5, 1 940 3 Sheets-Sheet 2 INVENTORS Charles, C. Cline LeonR-Pz'card ATTORNEYS y 1942- v c. c. CLINE ETAL 2,290,315

BUCKET DREDGE Filed April 5, 1940' ssneeis-sheet s INVENTOR S Charles C. .CZme

Leon P. Pzcard ATTORNEYS Patented July 21, 1942 BUCKET DREDGE Charles C. Cline and Leon P. Picard, Oamanche, Calif.

Application April 5, 1940, Serial No. 327,974

6 Claims.

This invention relates to gold dredgers of the endless bucket-line type. In these dredgers, the buckets dig the gravel, etc., from below water level, elevate it some distance, and then discharge it into a hopper or chute which conveys it to a screen or other device for separating and recovery of the values in the gravel.

The discharge of the material from the buckets is of course accomplished when the buckets become inverted as they pass about the top sprocket of the endless chain on which the string of buckets is mounted, and while the hopper catches the bulk of the material from the inverted buckets, a certain percentage is unavoidably I spilled between the hopper and the lip of the buckets.

Various devices have been used in an endeavor to catch this spilling material which otherwise drops back into the deck well and thence sinks -to the bottom, but such devices have proven somewhat inefficient and have only been able to catch a relatively small percentage of the spilled material.

The principal object of our invention is to eliminate this inefiiciency in operation by the provision of a device which will positively catch practically all of the spilled and otherwise Wasted material, and will deliver the same to an auxiliary screen for the recovery of any values therein. It has in fact been proved that the use of my device on a dredger, replacing previous devices for the same purpose, results in an increase of and up of the total values recovered. We have also provided what we believe to be certain novel features of construction and mounting of the auxiliary screen.

A further object of the invention is to produce a simple and inexpensive device and yet one which will be exceedingly effective for the purpose for which it is designed.

These objects we accomplish by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims.

In the drawings similar characters of reference indicate corresponding parts in the several views:

Figure 1 is a side elevation of our auxiliary screen and feed structure, shown in association with the bucket line and main screen unit of a dredger, the latter features being illustrated somewhat diagrammatically.

Figure 2 is an enlarged sectional elevation of the auxiliary screen unit.

Figure 3 is a transverse section on line 3-3 of Fig. 2.

Figure 4 is a fragmentary front view of the grizzly plate of the dredger showing the catch and feed-in hopper for the auxiliary screen.

Referring now more particularly to the characters of reference on the drawings, the conventional dredger includes an endless chain I on which is mounted a line of digging buckets 2. The line extends some distance above the deck 3 of the dredger and at the top passes over a direction changing sheave 4, so that the buckets as they turn about the sheave from in front become inverted. With such invention, the material in the buckets discharges into a chute 5 leading to a downwardly sloping screening device 6.

Such of the material as inevitably spills between the buckets and chute is caught by a plate 1 which extends downwardly from chute 5 to the deck Well 8 through which the bucket line passes back into the water.

The above construction is standard, and we do not alter this general arrangement in any way in applying my novel structure thereto, except that the usual grizzly is replaced by the unbroken plate 1 as shown. Such structure comprises a concentrator in the form of a rotary cylindrical screen or trummel disposed behind or rearwardly of the plate 1 under and substantially parallel to screen 6, and relatively small as compared therewith. The trummel comprises nonperforate end sections 9 with screen sections l0 therebetween, and while the screening is here shown conventionally, it is preferably formed of perforated plate, tied to the end sections by 1ongitudinally extending ribs or bars H.

The forward section carries a track band l2 engaged by supporting rollers [3, as is common practice. some distance beyond the rear end of the trummel is a tubular stub shaft M, disposed axially thereof, and rigidly connected to the rear section 9 by arms P5. The shaft turns in a bearing box It mounted for swivel movement in a vertical plane on supporting brackets H. In this manner, the trummel can yield without binding at any point in the event that any gravel, etc., should temporarily get between the track band and rollers.

A bevel gear I8 is mounted on shaft M at its rear end, and is engaged by a driven bevel pinion 19 disposed to one side of the gear.

A stationary spray pipe 20, connected to a source of supply under pressure, extends lengthwise through the trummel near the top, and then deflects toward the shaft It and passes through the same, terminating beyond the shaft in a downwardly depending portion 28 having a normally closed valve 22 therein for clean-out purposes. The pipe is suitably supported adjacent the forward end of the trummel as at 23, and also rearwardly of shaft M by a bracket device 24.

Fine material passing through the screening I0 falls into a riffle sluice 25 leading readwardly a certain distance beyond the trummel, said sluice having upstanding Wings 26 along the portion thereof directly under the screening. A water feed pipe 21 preferably delivers into the sluice at its head end. The pipe portion 2| also discharges into the sluice.

The large waste material passing out through the rear end of the trummel is caught by a laterally extending chute or apron 28 disposed above sluice 25 and delivering into another sluice 29 which leads forwardly and discharges into the well 8.

Material is delivered into the front end of the trummel by an open front hopper which includes a mouth portion 30 projecting through the plate 1 from in front of the same and thence into the trummel, and side wings 3| flaring upwardly from the hopper in front of the plate to a termination adjacent the side edges thereof, some distance below chute 5, so as to be then spaced apart a distance greater than the width of buckets 2. In practice, the plate is cut away for an area outlined by the wings and adjacent portion of the hopper mouth, and a back plate 32 is disposed between the wings having a rearward slope to the mouth relative to the plate I, so as to increase the width of the wings and thus provide a large material catching area without having them project far enough in front of the grizzly plate to possibly interfere with the buckets. In this manner, any and all material discharged from the buckets and not deposited in the chute, is caught by the wings and portion 39 and delivered to the auxiliary screen.

The apron 2B is preferably provided with perforations 23a over the chute 25, so that relatively small matter with the large waste material on said apron may drop down into chute 25.

It is to be noted that plate I is actually a special one, replacing the usual perforated grizzly plate or grizzly bars sometimes used, as previously stated.

From the foregoing description it will be readily seen that we have produced such a device as substantially fulfills the objects of the invention as set forth herein.

While this specification sets forth in detail the present and preferred construction of the device, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claims.

' Having thus described our invention, what we claim as new and useful and desire to secure by Letters Patent is:

1. A concentrator comprising a rotary screening unit, a frame structure, rollers mounted on said structure and supporting the unit adjacent one end, a stub shaft fixed in axial connection with the opposite end of the unit, a bearing in which said shaft is turnable, lateral trunnions projecting from said bearing, and bearing members fixed on the frame structure in which said trunnions are turnable,

2. In a dredge which includes an endless bucket line having a downwardly moving reach disposed at a forward slope, the buckets on said reach being inverted, a chute disposed with its upper end adjacent but clear of the upper portion of said reach and its supported buckets, said chute being in position to catch material initial- .ly discharged from the buckets upon inversion thereof, a values recovery mechanism into which the chute discharges, another values recovery mechanism on the dredge below said chute, and means intermediate said chute and said other mechanism to divert into the latter that spillage from the buckets which falls between said reach and said chute; said means comprising a solid plate of substantial width extending downward some distance from the upper end of the chute in substantial parallelism to said forwardly sloping reach but in clearance relation to the inverted buckets thereon, said plate having an opening therethrough communicating with said other mechanism, and deflector members mounted on the face of said plate and projecting toward said reach, said members being operative to deflect through said opening substantially all said spillage fiowing down the plate from above said opening 3. A structure as in claim 2 in which said deflector members are arranged to form a hopper, said hopper being open on top and at the front; said opening communicating with the bottom of the hopper.

4. In a dredge which includes an endless bucket line having a downwardly moving reach disposed at a forward slope, the buckets on said reach being inverted, a chute disposed with its upper end adjacent but clear of the upper portion of said reach and its supported buckets, said chute being in position to catch material initially discharged from the buckets upon inversion thereof, a values recovery mechanism into which the chute discharges, another values recovery mechanism on the dredge below said chute, and means intermediate said chute and said other mechanism to divert into the latter that spillage from the buckets which falls between said reach and said chute; said means comprising a solid plate of substantial width extending downward some distance from the upper end of the chute in substantial parallelism to said forwardly sloping reach but in clearance relation to the inverted buckets thereon, said plate having an opening therethrough communicating with said other mechanism, and an open front hopper formed with said plate and. into which hopper said spillage flows from the plate, said hopper including a lower mouth portion projecting through said opening from a point in front of the same and delivering at its rear end into said other mechanism, and divergent wings on the plate projecting upwardly from the sides of the mouth portion to a termination at points spaced apart a greater distance than the width of the buckets.

5. A structure as in claim 4 in which the hopper includes a back plate between the wings extending downward from adjacent the top of the wings and at a rearward slope to said solid plate to the mouth portion rearwardly of said solid plate.

6. A concentrator comprising a rotary openended screen unit, means freely supporting the unit at one end, a tubular stub shaft fixed in axial connection with the opposite end of the unit, a bearing for said shaft, means mounting said bearing for swivel movement in a vertical plane, and a stationary spray pipe passing through the unit from end to end, and through the stub shaft axially; the internal diameter of said tubular stub shaft being substantially greater than the outside diameter of the corresponding portioin of said spray pipe to permit of said movement of the bearing to a limited extent without obstruction by said corresponding portion of the spray pipe.

CHARLES C. CLINE. LEON P. PICARD. 

